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1.
Observations on a beef cattle farm in Flanders led to the suspicion of resistance to levamisole in a strain of Ostertagia ostertagi. After treating a group of six animals with levamisole (5 mg kg-1 L.W., i.m.) the reduction in the number of trichostrongylid eggs per gram of faeces varied between 0 and 66.6%, whereas a similar group treated with fenbendazole (7.5 mg kg-1 L.W., p.o.) showed a reduction in worm burdens of 100%. Coproculture showed that the remaining eggs in the first treatment group were all Ostertagia sp. The suspected field strain was compared with a reference strain of O. ostertagi by means of the in vitro larval paralysis test. This test showed LC95 values of 9.12 micrograms ml-1 and of 99.04 micrograms ml-1 for the reference and the field strain respectively, which indicates a resistance factor for the latter of 10.9. These results were not unequivocally confirmed by the post mortem findings on a tracer calf necropsied 4 days after treatment with levamisole. 相似文献
2.
The paper describes a method for detecting levamisole and morantel tartrate resistance by determining the percentage of paralysed third stage larvae in serial dilutions of anthelmintic. Levamisole resistantOstertagia spp. had a smaller proportion of larvae undergoing tonic paralysis in either levamisole or morantel tartrate than did a non-resistant strain. The dose response thus obtained for a strain of worms can be tested statistically against strains which are known to be resistant or non-resistant.Commonwealth of Australia 相似文献
3.
SUMMARY A field population of Trichostrongylus colubriformis was divided into 4 lines for exposure to selection in the laboratory. The first line was selected with 50 mg/kg thiabendazole, the second with 4 mg/kg morantel tartrate, the third with 50 mg/kg thiabendazole followed by 4 mg/kg morantel tartrate and the fourth line was not selected for drug resistance. Following at least 9 generations of selection there was no difference in LD50 or LD95 between the unselected and single selected strains of worms. The strain selected by50both thiabendazole and morantel tartrate had a significantly higher LD50 against thiabendazole, morantel tartrate and levamisole than did the other three strains. The single selected strains had LD95's of 172, 21.5 and 2.3 mg/kg for thiabendazole, morantel tartrate and levamisole respectively, compared with corresponding values of 111, 17.3 and 2.4 in the unselected strain and 124, 15.5 and 3.0 in the double selected strain. The estimated efficiency of the recommended dose of each anthelmintic against the unselected field strain was:—thiabendazole (44 mg/kg) 50% efficient, morantel tartrate (8.8 mg/kg) 76% efficient and levamisole (7.0 mg/kg) 99.9% efficient. 相似文献
4.
R K Prichard 《Veterinary parasitology》1988,27(1-2):97-109
Anthelmintic control of Ostertagia ostertagi in cattle presents some special problems because the arrested larval stage (hypobiotic EL4) tolerates all of the older anthelmintics. The only anthelmintics on the North American market that are effective against this stage as well as the adult and developing stages are ivermectin and fenbendazole. In addition to these, the newer broad-spectrum benzimidazoles and probenzimidazoles, albendazole, febantel, netobimin and oxfendazole, are effective and available in other countries. These anthelmintics can be used for prophylaxis of Type II ostertagiasis. The older anthelmintics, levamisole, morantel tartrate, thiabendazole, coumaphos, haloxon and phenothiazine, are effective against the adults and to some extent the developing stages of O. ostertagi so that they can be used to treat Type I ostertagiasis. They can also be used to prevent incoming larvae from establishing if they are administered continuously over a long period of time. This is possible with long term in-feed administration or by the use of the morantel slow release bolus. In cooler temperature regions, where cattle are housed over the winter, this bolus is given at turnout to remove any parasites in the animals and to kill incoming larvae for 60-90 days. This can prevent the build up of significant infective larvae on pasture so that very few arrested L4 larvae accumulate in the summer/autumn, effectively preventing Type II ostertagiasis from occurring later. The use of ivermectin and the newer benzimidazoles in intermittent or slow release devices should prove highly effective in the control of Type I and II ostertagiasis, as well as of subclinical ostertagiasis. To achieve maximum economic benefit, the use of anthelmintics should be based on sound epidemiological considerations, so that stock are not rapidly reinfected after treatment. 相似文献
5.
Christine Uhlinger VMD John Fetrow VMD MBA Colin Johnstone BVMS PhD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1988,2(3):113-116
A study was conducted to investigate the efficacy of six anthelmintics in a herd of dairy goats. Pretreatment larval cultures indicated that the goats were infected with Haemonchus contortus and Trichostrongylus colubriformis. Three separate treatment regimens were administered. In each trial, mature nonlactating goats were allocated into two treatment groups and a control group. Treatment groups received thiabendazole (TBZ) or levamisole (LEV), mebendazole (MBZ) or fenbendazole (FBZ), and morantel tartrate (MOR) or ivermectin (IVR). LEV, MOR, and IVR reduced fecal strongyle egg counts by 99% to 100% of pretreatment values. The benzimidazole (BZD) drugs changed pretreatment fecal egg counts by +2% to -32%. Results of posttreatment larval culture demonstrated the presence of H contortus larvae following the administration of BZD drugs. 相似文献
6.
R K Reinecke M Lourens B Petersen 《The Onderstepoort journal of veterinary research》1991,58(4):285-290
Two field trials, one with suckling Merino ewe lambs and the other with yearling Dohne Merino rams, are described. In these the anthelmintic efficacy of febantel (a benzimidazole), ivermectin, levamisole and morantel are compared, using the 1st stage larval reduction test. The mean natural log (+1 for zero values) of the post treatment larval counts of the treated groups was compared with that of the untreated controls and the percentage reduction used to assess anthelmintic efficacy. Febantel was only 87.4% effective against Teladorsagia in suckling lambs but the other anthelmintics were more than 99% effective against this genus. Efficacy against Haemonchus and Trichostrongylus ranged from 93.2%-100% for all 4 compounds. In the rams all compounds were 100% effective against Trichostrongylus, with the exception of morantel which was only 87.5% effective. None of the compounds were effective against Teladorsagia, particularly morantel, animals treated with which having more larvae than the controls. The interpretation of anthelmintic efficacy; the advantages of the first stage larval reduction test, compared with the faecal egg count reduction test; and the importance of incubating cultures at 30 degrees C for 24 h, in order to harvest first stage larvae, are discussed. 相似文献
7.
G C Coles J P Tritschler D J Giordano N J Laste A L Schmidt 《Research in veterinary science》1988,45(1):50-53
The growth, using freshly cultured Escherichia coli with ampicillin or heat-treated lyophilised E coli as a food source, of the larvae of the mouse nematode Nematospiroides dubius and the infectivity of resulting third stage larvae were determined. Concentrations of E coli between 0.5 and 1 mg dry weight ml-1 permitted optimal larval development for both N dubius and Trichostrongylus colubriformis. Development of larvae of susceptible and cambendazole-resistant strains of Haemonchus contortus in thiabendazole solutions showed clear differences between the strains and the larval development test was more sensitive than the egg hatch test. The test also detected a levamisole resistant strain of H contortus, although the degree of resistance could not be adequately measured. It is concluded that the test can be run with any anthelmintic to which resistance is suspected. 相似文献
8.
J A van Wyk P C van Schalkwyk H M Gerger E L Visser R M Alves L van Schalkwyk 《The Onderstepoort journal of veterinary research》1989,56(4):257-262
A strain of Haemonchus contortus from the Pietermaritzburg district of Natal was found to be resistant to levamisole (geometric mean efficacy 76.5%), morantel (41.9%), the benzimidazoles (oxfendazole: 33.7%) and rafoxanide (82.0%), but apparently fully susceptible to closantel and disophenol. In the case of ivermectin, a mean of 5.2% of the H. contortus was not removed at a dosage of 200 micrograms kg-1 live mass. A second strain of H. contortus, from Amsterdam in the south-eastern Transvaal, showed reduced susceptibility to levamisole (80.8%) and morantel (46.2%), the only 2 drugs tested. This is apparently the first report of resistance to the levamisole/morantel group of anthelmintics in sheep in South Africa. 相似文献
9.
N C Sangster H V Whitlock I G Russ M Gunawan D L Griffin J D Kelly 《Research in veterinary science》1979,27(1):106-110
Field strains of Trichostrongylus colubriformis and Ostertagia circumcincta, designated PF4 and PF5 respectively, were recovered from a farm on which the sole use of levamisole over a preceding 12 year period led to the development of anthelmintic resistance. The results of field observations and preliminary critical trials in both Merino and crossbred sheep showed that both species have varying degrees of resistance to three major anthelmintics; levamisole, morantel tartrate and thiabendazole. Mean worm count reductions for adult T colubriformis (PF4) for therapeutic doses of morantel tartrate, thiabendazole and levamisole in crossbreds were 45.7 per cent, 97.3 per cent and zero respectively, and for Merinos 80.7 per cent, 88.3 per cent and 92.0 per cent respectively. Against O circumcincta the corresponding reductions for crossbreds were 51.4 percent, 95.4 per cent and 20.3 per cent and for Merinos, 52.5 per cent, 73.1 per cent and 29.8 per cent. There was no statistically significant difference in the responses of both parasite species to either levamisole or morantel. This result suggests that resistance to the two chemically unrelated drugs may be co-inherited. 相似文献
10.
Twelve calves were raised helminth-free until 9 weeks of age when six were orally inoculated with 100,000 Ostertagia ostertagi infective stage larvae (L3). Three uninfected and three experimentally infected calves received intradermal injections of sterile saline and soluble larval extract (SLE) from O. ostertagi L3 with a protein concentration ranging from 1 to 200 micrograms ml-1. Biopsies were performed 48 h post-injection. A kinetic study was performed on the remaining six calves, three infected and three uninfected, using a 100 micrograms ml-1 concentration of SLE and taking biopsies 1, 4, 8, 12, 24, and 72 h post-injection at both the saline and SLE-injected sites. All calves had an immediate wheal and increase in skin thickness at the SLE-injected sites. The numbers of eosinophils infiltrating SLE-injected sites as compared to saline-injected sites were significant in both uninfected and infected calves, but the infected calves had significant numbers to a wider range of SLE concentrations and had significantly higher numbers than uninfected calves in the kinetic study. Infected calves also had significant numbers of basophils in the dose response study at concentrations of 5 and 100 micrograms ml-1 SLE. Neutrophil infiltration was similar in both groups and was significant at SLE-injected sites early in the kinetic study. Detectable mast cells were decreased in SLE-injected sites of infected animals and perivascular accumulation of mononuclear and some polymorphonuclear cells was observed in the deep dermis of infected animals. 相似文献
11.
Q. A. McKELLAR E. W. SCOTT P. BAXTER L. A. ANDERSON K. BAIRDEN 《Journal of veterinary pharmacology and therapeutics》1993,16(1):87-92
Morantel could not be detected (<0.05 pg/ml)in the plasma of cattle or goats followingthe oral administration of morantel tartrate at a dose rate of 10 mg/kg
bodyweight. No morantel was detected in the milk of lactating goats except in
one animal where a concentration of 0.092 pg/ml was detected at 8 h after drug
administration. Morantel was highly effective against Cooperia oncophora infec-
tions in calves treated 6, 9 or 18 days after infection; however, was highly
effective against Ostertagia ostertagi only when treated 18 days after infection.
Morantel did not affect the fecundity of adult 0.ostertagi surviving treatment 18
days after infection which had similar average numbers of eggs in their uteri
(range 13.4 f 0.73-16.8 L 0.98) as did parasites from control animals (range
12.0 k 0.70-13.6 2 0.66). Morantel could be detected at a concentration of 96 k
4.5 pgig (dry weight) in the faeces of a calf 24 h after treatment with I0 mgikg
bodyweight of morantel tartrate. The concentration of morantel in replicate
samples of this faeces exposed to natural atmosphere, but not to soil or soil
organisms, declined slowly over the following 322 days. At day 322 after the start
of the experiment 8.8 pg/g of morantel could be measured in the remaining
faecal material. Throughout the faecal degradation study the concentration of
morantel in the crusts of the replicate sample pats was lower than the
concentration in the core samples. 相似文献
bodyweight. No morantel was detected in the milk of lactating goats except in
one animal where a concentration of 0.092 pg/ml was detected at 8 h after drug
administration. Morantel was highly effective against Cooperia oncophora infec-
tions in calves treated 6, 9 or 18 days after infection; however, was highly
effective against Ostertagia ostertagi only when treated 18 days after infection.
Morantel did not affect the fecundity of adult 0.ostertagi surviving treatment 18
days after infection which had similar average numbers of eggs in their uteri
(range 13.4 f 0.73-16.8 L 0.98) as did parasites from control animals (range
12.0 k 0.70-13.6 2 0.66). Morantel could be detected at a concentration of 96 k
4.5 pgig (dry weight) in the faeces of a calf 24 h after treatment with I0 mgikg
bodyweight of morantel tartrate. The concentration of morantel in replicate
samples of this faeces exposed to natural atmosphere, but not to soil or soil
organisms, declined slowly over the following 322 days. At day 322 after the start
of the experiment 8.8 pg/g of morantel could be measured in the remaining
faecal material. Throughout the faecal degradation study the concentration of
morantel in the crusts of the replicate sample pats was lower than the
concentration in the core samples. 相似文献
12.
N Maingi 《Veterinary parasitology》1991,39(3-4):285-291
Resistance to thiabendazole (TBZ), fenbendazole (FBZ) and levamisole (LVM) in naturally acquired gastrointestinal nematode parasites in sheep was investigated on a farm where anthelmintic resistance was suspected. This was measured by both the in vitro egg hatch assay, and reductions in faecal egg and worm counts in treated animals. In the egg hatch assay, nematode eggs were incubated in various concentrations of either TBZ or LVM. The level of resistance was expressed as the drug concentration inhibiting 50% of the eggs from hatching (LC50). The nematode population had LC50 values of 0.26 microgram ml-1 TBZ and 3.12 micrograms ml-1 LVM. In the faecal egg and worm count reduction test, naturally infected sheep were treated with either TBZ (88 mg kg-1), FBZ (10 mg kg-1) or LVM (15 mg kg-1). Faecal egg and total worm counts from these sheep were then compared with counts from untreated sheep. TBZ, FBZ and LVM failed to reduce the faecal egg counts and total worm counts by more than 90%. Based on the identification of larvae from faecal cultures, the most predominant nematode species in the resistant population were Haemonchus (62%) and Trichostrongylus (28%). TBZ reduced faecal egg counts for both species by less than 90%. FBZ and LVM also reduced Haemonchus spp. eggs by less than 90%. Other nematode species numbers did not satisfy criteria for the determination of efficacy. 相似文献
13.
Therapeutic and prophylactic efficacy of morantel when administered directly into the rumen of cattle on a continuous basis 总被引：1，自引：0，他引：1
R M Jones 《Veterinary parasitology》1983,12(3-4):223-232
The efficacy of morantel tartrate when administered on a continuous basis directly into the rumen/reticulum of cattle, either by a cannula or from a specially designed device, was evaluated against gastrointestinal parasites under laboratory conditions. In two experiments the continuous infusion of morantel at rates between 0.26 and 1.04 mg/kg body weight per day using a peristaltic pump was highly efficacious in both preventing the establishment of infections and removing established infections of the following species: Ostertagia ostertagi, Haemonchus contortus, Cooperia oncophora and Trichostrongylus colubriformis. The same dose rates also prevented establishment of Dictyocaulus viviparus infection but were ineffective against established infections of this parasite. In another two experiments the continuous release of morantel tartrate for at least 60 days (at rates between 0.65 and 1.11 mg/kg body weight per day) from a specially designed intraruminal sustained release bolus (secured at each end by a polyethylene impregnated semi-permeable membrane) was highly efficacious in both preventing the establishment of infections and removing established infections of the following species: O. ostertagi, T. axei, T. colubriformis and C. oncophora. 相似文献
14.
Twelve 9-week-old calves were divided into four groups; two groups were maintained helminth-free as controls and the other groups were given Ostertagia ostertagi infective-stage larvae (L3) orally. One group received 100,000 L3 as a single inoculum and the other group received L3 in increasing dosages at weekly intervals for 8 consecutive weeks. The blastogenic responses to concanavalin A (Con A), phytohemagglutinin (PHA), and a soluble larval antigen from O. ostertagi (SLA) of peripheral blood lymphocytes were evaluated using tritiated thymidine incorporation into DNA as a measure of blastogenesis. The responses to Con A of all infected calves were significantly depressed while the responses to PHA were not. SLA, at concentrations of 4 micrograms ml-1 and above, caused blastogenic activity in lymphocytes from uninfected calves. Using SLA at 1 microgram ml-1 in lymphocyte cultures supplemented with autologous serum, an antigen-induced blastogenic response was detected in calves receiving serial inoculations of L3. 相似文献
15.
The anti-mycoplasma effects of the ionophores (lasalocid sodium, monensin and nigericin) were compared with that of tylosin tartrate and tiamulin in vitro. Forty-four strains representing 14 avian and 10 mammalian Mycoplasma species and serotypes and 5 Acholeplasma species were tested. The ionophores showed average minimal inhibitory concentration (MIC) values between 3.65 and 4.93 micrograms ml-1 for all strains, the MIC values for glucose-fermenting strains were between 2.26 and 3.75 micrograms ml-1, significantly lower than for arginine-hydrolysing strains (9.27-13.12 micrograms ml-1). These values were significantly higher than those obtained with tylosin tartrate (0.45 micrograms ml-1) or tiamulin (0.13 micrograms ml-1). The ionophores were more efficacious against acholeplasmas (0.06-0.25 micrograms ml-1) than against mycoplasmas. 相似文献
16.
Two field strains of Trichostrongylus colubriformis were tested by in vitro and in vivo methods for resistance to morantel, levamisole and thiabendazole and compared with an anthelmintic-naive laboratory-passaged strain (McM). One field strain (TAS) was isolated from a dairy goat herd which had experienced severe helminthiasis despite intensive anthelmintic usage. The other (BCK) was isolated from sheep which had been treated solely with levamisole over a 6-year period. The BCK strain had very high levels of both levamisole and morantel resistance. In contrast the TAS strain was resistant to morantel but highly susceptible to levamisole. This finding is contrary to the expectation that selection with morantel automatically confers resistance to levamisole, the converse of which was shown to apply in the BCK strain. Although the TAS strain was exposed to levamisole prior to isolation, examination of the drug's pharmacokinetics in goats indicated that it exerted little if any anthelmintic effect, and therefore selection pressure, on the parasite population. This study suggests that the mechanism of levamisole resistance covers a wide spectrum, and embraces that for morantel. It also suggests that in order to conserve the effectiveness of the levamisole/morantel group of broad spectrum anthelmintics, morantel should be used to the exclusion of levamisole until resistance is detected, at which time levamisole may be introduced to re-establish high levels of control. 相似文献
17.
Electronic measurements of the motility of third stage larvae of a susceptible and a levamisole/benzimidazole-resistant strain of Haemonchus contortus were made after incubation in solutions of anthelmintics for 24 h. Results confirmed the resistance to benzimidazoles, but failed to show differences in response to levamisole. Visual observations of paralysis of first and third stage larvae in solutions of levamisole also failed to show significant differences between the two strains. The tests as conducted failed to demonstrate levamisole resistance, suggesting that nematode strains may vary in their mechanisms of resistance to levamisole. 相似文献
18.
Evaluation of the morantel sustained release trilaminate in the control of parasitic gastroenteritis in first season grazing cattle 总被引：1，自引：0，他引：1
A novel intraruminal bolus developed for the sustained delivery of the anthelmintic morantel tartrate was evaluated in the seasonal control of parasitic gastroenteritis in first season grazing calves. The morantel sustained release trilaminate is a trilaminate sheet consisting of a central lamina of a morantel tartrate/ethylene vinyl acetate matrix coated on both sides with a thin impermeable layer of ethylene vinyl acetate. A symmetrical pattern of circular perforations punched through the device controls the release of morantel. Administration of the trilaminate to calves significantly reduced their faecal egg output compared with untreated controls and thus reduced pasture larval contamination. Clinical parasitic gastroenteritis was prevented in the treated calves and there were significant reductions in their worm burdens compared with the untreated control calves both during and at the end of the grazing season. The control of parasitic gastroenteritis resulted in a significantly greater (P less than 0.0001) weight gain, of 45 kg, by the treated calves. 相似文献
19.
L G Rickard G L Zimmerman E P Hoberg P W Lockwood D W Weber R Miller 《Veterinary parasitology》1989,33(2):125-133
The effectiveness of the morantel sustained release trilaminate (MSRT) in controlling gastrointestinal nematodes through a grazing season was evaluated using 60 yearling beef stocker calves randomly divided into 2 groups of 30 animals each. In April 1985, the calves comprising the treatment group each received an MSRT designed to release morantel tartrate continuously for 90 days while those of the control group remained unmedicated. All animals were weighed and samples of rectal feces were taken at 14-day intervals, beginning on Day 0, until trial termination (Day 168). At trial termination, 10 control and 10 treated calves were necropsied for recovery of gastrointestinal nematodes. Three sets of parasite-na?ve tracer calves were utilized to evaluate the initial, interim and final levels of pasture contamination by nematode larvae. Overall, the use of the MSRT resulted in a 75.5% reduction (P less than 0.001) in output of nematode eggs from the principals, an 81.8% reduction (P less than 0.001) in numbers of gastrointestinal nematodes in principals (at trial termination), and a 96.9% reduction (P less than 0.05) of pasture larval nematode contamination (as indirectly indicated by parasite burdens in tracer calves). The mean weight advantage of treated calves was 16.6 kg per head (P less than 0.001). 相似文献
20.
The efficacies of fenbendazole and thiabendazole against artifically acquired cattle nematodes and the efficacies of fenbendazole, prabendazole and levamisole against naturally acquired cattle nematodes were studied in western Victoria. Fenbendazole significantly (P less than 0.05) reduced numbers of late and early fourth stage larvae (greater than 96%), artificially acquired Cooperla spp (100%) and naturally acquired adult Ostertagia ostertagi (98%) and Trichostrongylus axei (90%). Thiabendazole significantly reduced numbers of artificially acquired late fourth stage larvae (83%) and parbendazole significantly reduced numbers of adult O. ostertagi (72%) in one group of cattle. Fenbendazole was the most effective anthelmintic. 相似文献